The present invention is generally in the field of fluid tanks and valves for fitting in such tanks. In particular the invention is concerned with connecting a valve to the tank and a suitable tank therefor.
A variety of valving means may be fitted for different types of fluid tanks for different requirements. Typical examples are a vehicle""s fuel tank, a mobile fluid container, various containers used in different industrial and chemical processes, etc.
It is common practice to connect a valve to a tank by performing an aperture of a size comfortably accommodating the valve""s housing, and fixedly attaching the valve by various means, e.g. welding, heat welding, different fasteners, etc. However, this arrangement has several drawbacks. First, it is necessary to provide special sealing means between the valve""s housing and the tank. Second, the assembly of each valve is relatively time consuming.
Second, as a consequence of the above arrangements, the external surface of a tank holding such one or more valves also carries at least a portion of an outlet nozzle and tubing connected thereto, as well as, in some cases, also some electrical wiring. This renders accessibility poor and requires special space design and other considerations.
Still another serious problem is concerned in particular with fuel tanks used in vehicles. It is now an ever-growing requirement of environment concerned organizations and authorities that the rate of fuel permeability from the fuel tank and its accessories be minimal. The outcome of this requirement is that new connection means are now required for ensuring essentially permeation-free connection between the valves and the fuel tank.
Still another consideration concerned with connection of valves to tanks is the effective operation level of the valves, namely the level at which the valve closes (at times referred to as cut-off or shut-off and the level at which the valve reopens. One of the considerations governing the operative level is space consuming which is of significant importance [[in]] particular in vehicles. It is thus a requirement that the xe2x80x9cdead spacexe2x80x9d i.e. the space between xe2x80x9cmaximum fuel levelxe2x80x9d and the top wall of the fuel tank, be reduced to minimum. However, by inserting the valve into the tank, care has to be taken not to increase the dead space.
It is a first object of the present invention to provide a novel concept for connecting valves to fluid tanks. It is a further object of the invention to provide a tank for accommodating such valves.
In accordance with a first of its aspects, the invention provides a valve fitted within a fluid tank, the valve comprising a housing fitted with one or more fluid inlet ports, and an outlet port, said housing accommodating a float-type valve member axially displaceable within the housing responsive to fluid level within the tank, between an open position in which the outlet port is open, and a closed position in which the outlet port is sealingly closed;
the valve characterized in that the housing is integrally formed with a nozzle member, said nozzle member being in flow communication with the outlet port and having a main portion with an outlet thereof extending within the tank.
By a preferred embodiment, the entire valve is received within the fluid tank wherein in accordance with a first application, the housing of the valve is formed at an uppermost portion thereof with a stem member for fixedly receiving within a corresponding hole formed at a top wall of the tank. The hole formed in the tank may be a through-going hole or a blind bore.
By a second application, the housing of the valve is formed at a top portion thereof with a first connecting member adapted for engagement with a corresponding, second connecting member integral with a top wall of the tank. Preferably, the first and the second connecting members constitute together a snap-type connection.
In order to minimize the so-called dead space within the tank, a top wall portion of the housing abuts against a bottom surface of the top wall of the tank. Furthermore, in order to decrease the dead space, the housing comprises at least one opening at or adjacent a top end thereof, and one or more openings at a bottom end of the housing.
By a preferred embodiment the inlet openings into the tank are concealed by a wall portion extending from the housing. This arrangement prevents splashing, resulting in unstable positioning of the valve.
Preferably, the valve in accordance with the invention is fitted into a fuel tank of a vehicle, whereby the valve is a fuel valve having one or more of the following functions (all being venting valves): roll-over valve (ROV), and over-filling interdictions valve (OFI), and filling-limit vent-valve (FLVV).
In some cases, where there is a stem member extending from a top surface of the valve through a corresponding aperture formed at a top wall of the tank, said aperture is preferably sealingly covered with a patch member, said patch member being impermeable to fuel vapor. In accordance with such an arrangement, the patch member is attached to an external face of the tank in a non-permeable manner.
By another embodiment of the invention, there may be formed a cavity at a top wall of the tank, said cavity accommodating at least a portion of the valve""s housing. The cavity may be an indention formed in the top wall of the tank or, a tubular extension from the top wall with an open end, the open end being sealed with a suitable cover element. According to one arrangement, the housing is formed with a snap-engagement arrangement for snapingly engagement within the corresponding cavity. Preferably, the main portion of the nozzle member extends from, or adjacent, a bottom end of the housing.
Where the top wall of the tank is formed with a cavity, it is preferred that one or more first, bottom inlet port of the housing extend [[at]] or adjacent a bottom surface of the top wall of the tank, and one or more second, top inlet port extend within the cavity, said one or more second inlet port being in flow communication with the interior space of the tank. This arrangement eliminates or reduces to minimum the dead space within the tank.
Wherein the housing is received within a corresponding cavity formed at a top wall of the tank, there is preferably provided a sealing arrangement between the valve and the walls of the cavity.
In accordance with one specific arrangement, the housing is formed at a top end thereof with a laterally extending wall portion adapted for resting over a top surface of a top wall of the tank. In accordance with this arrangement, the housing is formed with an opening sized to accommodate the housing, and where said laterally extending wall portion is larger than said opening.
Still preferably, in accordance with this embodiment, the opening formed at the top wall of the housing is sealingly covered with a patch member, said patch member being impermeable to fuel vapor.
According to a preferred design, the main portion of the nozzle member extends adjacent a bottom surface of a top wall of the tank.
By a preferred design of the valve, the outlet port is a slit-like aperture inclined with respect to a longitudinal axis of the valve and wherein a top surface of the valve member facing said aperture, is substantially equally inclined with respect to the longitudinal axis, and where an elongated flexible closure membrane strip is anchored only at one end thereof to a top surface of the valve member. Suitable means are provided to prevent rotation of the valve member within the housing.
According to a second aspect of the invention, there is provided a fluid tank for fixedly receiving a valve as described herein-above. In accordance with this second aspect, there is provided a fluid tank fitted for receiving at a top wall thereof a valve, said valve comprising a housing fitted with one or more fluid inlet ports and an outlet port, said housing accommodating a float-type valve member displaceable within the housing responsive to fluid level within the tank, between an open position in which the outlet port is open, and a closed position in which the outlet port is sealingly closed;
the tank characterized in that the valve is entirely received within the tank and the valve depends from the top wall.
In accordance with the second aspect of the invention, the fluid tank is fitted at a bottom surface of the top wall thereof, with a connecting member adapted for engagement with a corresponding member formed at an uppermost portion of the housing of the valve.
In accordance with one specific embodiment, the tank is formed at a top wall thereof with a cavity sized to accommodate the valve. Said cavity typically accommodates essentially the entire valve whereby the main nozzle portion extends from or adjacent a bottom end of the housing of the valve. By one embodiment, the cavity is [[a]] tubular-shaped, extending upwardly from a top surface of the tank.
Preferably, the cavity formed in the tank comprises snapping means for engagement with the walls of the valve. Still preferably, the housing is sealingly received within the cavity of the tank.